<form action="<?php echo $action; ?>" method="post" id="checkout">
<input type="hidden" name="Ds_Merchant_Amount" value="<?php echo $amount; ?>">
<input type="hidden" name="Ds_Merchant_Currency" value="<?php echo $currency; ?>">
<input type="hidden" name="Ds_Merchant_Order"  value="<?php echo $order; ?>">
<input type="hidden" name="Ds_Merchant_MerchantData" value="<?php echo $order_id; ?>">
<input type="hidden" name="Ds_Merchant_MerchantCode" value="<?php echo $merchant_code; ?>">
<input type="hidden" name="Ds_Merchant_Terminal" value="<?php echo $terminal; ?>">
<input type="hidden" name="Ds_Merchant_TransactionType" value="<?php echo $transaction_type; ?>">
<input type="hidden" name="Ds_Merchant_MerchantURL" value="<?php echo $merchant_url; ?>">
<input type="hidden" name="Ds_Merchant_UrlOK" value="<?php echo $url_ok; ?>">
<input type="hidden" name="Ds_Merchant_UrlKO" value="<?php echo $url_nok; ?>">
<input type="hidden" name="Ds_Merchant_MerchantSignature" value="<?php echo $signature; ?>">
</form>
<div class="buttons">
  <table>
    <tr>
      <td align="left"><a onclick="location = '<?php echo $back; ?>'" class="button"><span><?php echo $button_back; ?></span></a></td>
      <td align="right"><a onclick="$('#checkout').submit();" class="button"><span><?php echo $button_confirm; ?></span></a></td>
    </tr>
  </table>
</div>